Overview:

Internal and external rotation of the knee is a popular test especially in ski-ing populations. The popliteus and hamstrings muscles play a significant role in rotating the knee (internally and externally) to aid unlocking and locking the knee.

It should be noted that this position stretches the ligaments at t the rear of the knee and can impinge the meniscus (cartilages) at the posterior horns.

This could be the effect you want some patient populations (like ski-ing) but in many cases can lead to injury.

Care should be exercised if using this test.

 

 

 Supine Lying position:

In this position there is the increased innate thoracic and pelvic stability (little rotation occurs) but the angle of the knee has to be considered with the knee at 90 degrees results tend to be higher than the other most popular angle 45 degrees.

ankleinvsupine

Stabilisation:

Lying: in the lying position stabilisation usually involves holding the bed handles. Most manufacturers supply a thigh / calf stabiliser. Use the pelvic strap.

Attachments:

The footplate supplied with the machine should fully stabilise the foot it is likely the foot will pull to dorsi flexion during the test so care should be used to full tighten any straps

Axis of rotation:

The axis of rotation goes from the machine and extends through the center of the calcaneous (see below). To check the alignment simply rotate the foot and ensure the knee does not lift from the stabiliser.

ankleinvaxis 

Anatomical zero:

Foot points to roof.

Range of motion:

Large individual variations exist in the amount of movement. The ROM should be between 30-50 degrees internal rotation and 20-40 degrees external rotation. 

Gravity correction:

The effects of gravity are negligible in this position in fact some manufacturers use a counter balance rather than instrumented correction.

Speeds:

Speeds tend to be lower in internal external rotation of the knee with multiples of 30 being common. However, any speed from 30-240 degrees/second could be considered representative of the speed of subtalar movement during walking/running. A mid range speed for ordinary subjects is 45 degrees per second which will offer good results.

Generally it is accepted that speeds of 30 degrees/second and multiples of this should be used.

Knee Internal / External Rotation Protocols:

Muscles involved:

        Hamstrings and Gastrocnemius

 

Strength Test Protocols General Patients Athletes Research
Contraction Cycle con/con con/con 

con/con

con/ecc 

con/con

ecc/ecc

Speed/s 30 - 60 30 30-180 30-180
Trial Repetitions 0 0 3
Repetitions 10 10  10 5
Sets 3 4 up to 9
Rest between sets 20-30 secs 20-30 secs  20-30 secs 20 secs
Rest between speeds 2 minutes 2 minutes

2 minutes 

2-5 minutes
Rest between sides 5 minutes 5 minutes 

5 minutes 

5 minutes 
Feedback  nil nil  nil  nil 

 

Endurance Test Protocols General Patients Athletes Research
Contraction Cycle con/con con/con 

con/con

con/ecc 

con/con

ecc/ecc

Speed/s 60 30 60-180 60-180
Trial Repetitions 0 0 0
Repetitions Max Max Max Max
Sets 1 1 1
Rest between sets N\A N/A N/A N/A
Rest between speeds 10-15 mins 10-15 mins  10-15 mins 10-30 mins
Rest between sides 5 mins 5 mins  5 mins  5 mins 
Feedback  nil nil  nil  nil 

 

Strength Exercise Protocol General Patients Athletes
Contraction Cycle con/con con/con con/ecc
Speed/s 30 up to 60 30 30-180
Trial Repetitions 0 0 0
Repetitions 10 10 14
Sets 6 6 up to 12
Rest between sets 30-60 secs 30-60 secs 30 secs
Rest between speeds 2 mins 2 mins 2 mins 
Rest between sides Nil Nil Nil 
Feedback bar bar bar

 

Endurance Exercise Protocol General Patients Athletes
Contraction Cycle con/con con/con con/con
Speed/s 60 30 60-180
Trial Repetitions 0 0 0
Repetitions Max Max Max
Sets 1-3 1 1-3
Rest between sets 5-10 mins N/A 5-10 mins
Rest between speeds 10-30 mins N/A 10-30 mins 
Rest between sides Nil Nil Nil
Feedback bar/pie chart bar/pie chart bar/pie chart

 

Notes:

Test the uninvolved or dominant limb first. Extreme care must be taken to not damage the knee in this pattern.

 

Interpretation:

In the knee it is normal to look at the ratio between the right and left sides there should be a 0-10% difference between the sides. Anything beyond this would indicate a muscle imbalance which would be best corrected.

Eccentric results are generally 30% higher than concentric within the same muscle.

Concentric/concentric: internal/external rotation ratio should show a external rotation dominance of 10 percent.

Peak torque occurs in the internal rotators at 20 degrees and in the external rotators at 2 degrees (Hester & Falkel 1984).

Normative values:

All values Pt ftlbs      

Dominant

Internal

Non Dominant

Internal

Dominant

External

Non Dominant

External

Ostering et al. (1980) knee angle M 18-35        
30 deg sec 90     89.7 102.7 101.3 111.4
30 deg sec 45     78.1 77.4 83.2 81.0
               
Hester & Falkel (1984) 90 M 18-35        
30       28 24.7 28.2 25.6
60       25.4 22.8 25.6 24.1
120       20 18.5 20.1 19.2
180       16.2 15.1 16.9 15.5
PTBW ftlbs

Left

Internal

Left

External

Right

Internal

Right

External

30 14 15 16 16
60 13 14 15 15
120 11 11 11 11
180 9 9 9 10